GALLERY: Bella Vista Station update

Our tour of the eight new stations on the $8.3 billion North West Rail Link — which you can follow here online — takes us back to the Bella Vista tunnelling site which is almost ready to accept Elizabeth, the first of the four massive NWRL tunnel boring machines.

"In just over a year, Bella Vista has been turned into one of the two major tunnelling sites on Australia's biggest public transport project," a Transport for NSW (TfNSW) spokesman said.

"The station box area has been dug down almost 10 metres, the factory which will make the inside concrete lining of the tunnels is up and running and the tunnel entry points have been identified and marked out.

"From here, the first two TBMs will start digging nine kilometres to Cherrybrook [station].

"All four TBMs will deliver the twin 15-kilometre tunnels between Bella Vista and Epping — Australia's longest railway tunnels and the first time in Australia four TBMs have been used on a single construction job."

The factory making the 16,000 concrete rings which will line the inside of the twin 15-metre tunnels is now also up and running.

Overlooking the station box at the Bella Vista tunnelling site. The station itself will be built and fitted out as part of the operations contract, which will be awarded later this year. Picture taken 11 July, 2014, by Gene Ramirez

"At peak production, the concrete factory at the Bella Vista tunnelling site will be making two concrete segments every seven minutes," TfNSW's spokesman said.

"Each segment is poured and cooked in a 60-degree Celsius oven, then stacked to harden for 28 days before being transported into the tunnels on the back of special vehicles."

The tall silos on the Celebration Drive site are part of a plant which will produce grout, which is used to fill the joints between the precast concrete segments that will line the tunnels.

Steel slip ramps are now being fitted to the floor of the station area and large sections of Elizabeth — which is 120 metres long — will be lifted on to the steel ramps, ready to start tunnelling in October.